• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.152-159
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• 2010

A combustion flame under the overhead power lines may be caused by breakdown disturbances in power systems. In this study, experiments were conducted for the purpose of investigating the reduction in insulation strength caused by combustion flame and the shape changes of the flame, and flashover characteristics and extinction phenomena of the flame in the simulated conditions of overhead power lines were examined under the application of a.c. and d.c. high-voltages. As the results of the experimental investigation, it is demonstrated that flame can remarkably reduce breakdown voltages of the air-gap in shorter range of the gap distance. As the gap distance increases, flame was quenched, before the flashover, by corona wind generated from the needle electrodes.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.125-130
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• 1998

13Cr-1.5Nb-Fe alloy powder was fabricated by water atomization method, and ring-shape specimen of this composition was fabricated by oil press, and then sintered in the vacuum furnace. Powder shape, size distribution, composition (C, N, O, S) analysis and saturation magnetization of as-prepared 13Cr-1.5Nb-Fe alloy powder were investigated. Ac permeability and power loss was measured after forming and sintering process. Saturation magnetization and contents of oxygen of the alloy powder is160 emu/g and about 6000 ppm, respectively. 50 % volume fraction indicate particle size of 70$\mu$m. The ac permeability of sintered specimen increases with increasing sintering temperature and forming pressure. The power loss is 107 W/cc at sintering temperature of 1200 $^{\circ}C$, 12 ton/$\textrm{cm}^2$ forming pressure, and 20 KHz. It is the lowest among the prepared specimen.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.141-149
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• 2008

Because aluminum has a lighter weight and higher strength than iron, it is frequently used in the transportation industry for the purpose of reducing the weight of a chassis, and thereby increasing fuel efficiency. However, there are some difficulties with arc welding aluminum due to its lower melting point, high thermal conductivity and oxidation coating on its surface. This study proposed using superposition ac pulse MIG arc welding, which has been improved from the pulse waveform of conventional MIG welding. A MIG arc welding power source was developed to test the effectiveness of this method.

• 전기의세계
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• v.28 no.7
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• pp.49-55
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• 1979

This paper describes the mechanisms which breaks A.C. over-current protection in low voltage load. For the high speed over-current protection, it consists of thyristor switching circuit by forced commutation, IC logic gate controlled circuit and over-current detector with reed switch. Under various duty conditions, breacker was carried out several experiments and discussions. The results are as follows; (1) over-current cut off is possible within a quarter cycle (4ms at 60Hz) and clear is at least ten times faster than its electromechanical equivalent. (2) as the forced commutation thyristor circuit breaker has capability of high speed break, equivalent surgy current capacity of switching thyristor is increased more than twenty times of its rated current. (3) breaker using solid state dose not produce any harmful arc during switching period. Therefore the breaker above described may be considered an effective over-current protector for soli state power devices in industrial applications.

• KDI Journal of Economic Policy
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• v.13 no.4
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• pp.155-177
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• 1991

The promotion of economic exchange and cooperation between North and South Korea is significant in two ways. First, the pursuit of economic interest can lead gradually to the unification of the national economies. Second, economic relations can serve as the first stride toward political reunification. There are, however, many difficulties in conceiving a strategy for economic cooperation between North and South Korea because of their differences in ideology and socio-economic system. Under these circumstances, a bid by either the North or the South to consider its specific ideology or socio-economic system absolute and to impose them on the other side would inevitably lead to confrontation and collision and deepen the division of the country. Therefore, steps to expand and develop economic and technological cooperation and comprehensive exchanges between the North and the South, with due regard to the development of bilateral relations, are in full accord with the interests of the both sides. It is clear that North Korea's changing attitude toward its environmental conditions is neither a policy of opening nor an ideological shift toward pragmatism, as has occurred in the Eastern European countries. Instead, it is a temporary tactic for breaking out of the economic stagnation caused by its rigid economic structure. In this light, we must.

• Journal of the Korean Society of Child Welfare
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• no.27
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• pp.121-151
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• 2008

The purpose of this study is to examine the moderated mediation effects of parenting functioning on the relations between deviant peer's influences and delinquent behaviors in adolescence. To investigate the moderated mediation effects, simple slope test and bootstrapping method based on multiple linear regression(MLR) model were used. This study used data from wave 1-2(2003-2004) of the Korea Youth Panel Survey(KYPS). Results showed that poorer parenting increased the probability that adolescents would affiliated with deviant peers, and more association with deviant peers, in turn, was related to delinquency. There was statistical significant interaction between affiliation with deviant peers and parenting in the model for delinquency. It implied that the relation between deviant peers and delinquency depends on the quality of parenting. Finally, indirect effect of earlier parenting on delinquent behavior through affiliation with deviant peers was moderated by later parenting. These results help clarify the conditions under which exposure to parenting behaviors can buffer the negative effect of deviant best friends on delinquent behaviors in adolescence. Practice and policy implications as well as further research topic were discussed to aid the search for highly effective preventive and treatment interventions.

• Journal of Advanced Navigation Technology
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• v.18 no.2
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• pp.165-169
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• 2014

Digital load is increasing suddenly for various reasons, such as easy control and management. Accordingly, a consumption pattern of load is becoming DC. However, the power supply is supplied by AC power. The load power supply substantially needs DC power. AC power has to be converted to DC power. Renewable energy sources like solar, wind, fuel cells are DC power generation, but the transfer needs to through by AC power, thus DC power has to be converted to AC power. Resultantly, a multi-stage conversion loss is constantly increasing. The power distribution system of DC-based is required for effective use of these energy sources. This requires a DC load, as well as is necessary to develop DC ELCB which are able to detect DC leakage current for implementing protection. In this study, it realize detection algorithm about DC leakage current to verify the performance of the sensor and apply it to the ELCB which is based on DC. Therefore, it is expected to protect operating of DC power distribution system.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.550-556
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• 2018

This study conducted AHP analysis to find out the directional of human resource management through policy priorities for personnel innovation of local public officials. The results of the study were derived using the AHP analysis methodology. The results of the study are summarized as follows. First, the interchange of personnel system was the most important measure among the measurement areas of interchange of personnel system, education training system, recruitment management system and appointment management system. Second, from the point of view of evaluation item, it is as follows. In the personnel interchange system, it was found that the conversion of personnel management based on job performance and performance was important. In the position management system, it is important to appoint and expand professional positions. In the recruitment management system, the introduction of personality and aptitude tests used in the private sector is important. Development of customized curriculum programs is important in the education and training system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.4
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• pp.275-283
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• 2021

In this study, a driver IC for an AC-powered LED that can be manufactured with a low voltage semiconductor process is designed and the performances of the driver IC were simulated. In order to manufacture a driver IC that operates directly at AC 220V, a semiconductor manufacturing process that satisfies a breakdown voltage of 500V or higher is required. A semiconductor manufacturing process for a high-voltage device requires a much higher manufacturing cost than a general semiconductor process for a low-voltage device. Therefore, the LED driver IC is designed in series so that it can be manufactured with semiconductor process technology that implements a low-voltage device. This makes it possible to divide and apply the voltage to each LED block even if the input voltage is high. The LED lighting circuit shows a power factor of 96% at 220V. In the pnp transistor circuit, a very high power factor of 99.7% can be obtained, and it shows a very stable operation regardless of the fluctuation of the input voltage.

• The Transactions of the Korea Information Processing Society
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• v.2 no.6
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• pp.947-959
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• 1995

In this paper, we discuss an effort to develop a multi-agent architecture through which heterogeneous applications communicate and cooperate by means of plug-and play mechanism. Three componets are created in order to challenge the plug-and-play mechanism : meta-information, PnP agent module, and ICM. The meta- information is used to automatically set up a suitable configuration for a new plugged application, eliminating the need for direct addressing among heterogeneous applications. The PnPagent module is a homogeneous controller that operates on an application to ensure that its activities are coordin ated with those of the others within the community, provides a homogeneous communication envelope for all heterogeneous applications. The combination of these three components is used to meet the desire for implementing the plug-and-play mechanism. In this distributed, open architecture, one should be able to simply plug in a new application and it should work.